High density detergent-making process involving a moderate speed mixer/densifier

ABSTRACT

A process for producing high density detergent compositions is provided. The process is a continuous process during which high density detergent agglomerates are produced by feeding a surfactant paste and dry starting detergent material into a moderate speed mixer/densifier having a centrally positioned rotating shaft and at least one high speed chopper. The surfactant paste is inputted at least one location along the length of the moderate speed mixer/densifier to achieve optimal build-up agglomeration. The proces produces a free flowing, high density detergent composition which can be commercially sold as a low dosage or “compact” detergent composition.

This application is a 371 of PCT/US99/18657 filed Aug. 17, 1999 whichclaims benefit of Provisional Application No. 60/097,323 filed Aug. 20,1998.

FIELD OF THE INVENTION

The present invention generally relates to a process for producing highdensity detergent compositions having improved physical properties. Moreparticularly, the invention is directed to a continuous process duringwhich high density detergent agglomerates are produced by feeding asurfactant paste and dry starting detergent material directly into acylindrically-shaped/moderate speed mixer/densifier having a centrallypositioned rotating shaft and at least one high speed chopper or cutter.The process produces an improved free flowing, high density detergentcomposition with a narrow particle size distribution which can becommercially sold as a low dosage or “compact” detergent composition.

BACKGROUND OF THE INVENTION

Recently, there has been considerable interest within the detergentindustry for laundry detergents which are “compact” and therefore, havelow dosage volumes. To facilitate production of these so-called lowdosage detergents, many attempts have been made to produce high bulkdensity detergents, for example with a density of 600 g/l or higher. Thelow dosage detergents are currently in high demand as they conserveresources and can be sold in small packages which are more convenientfor consumers.

Generally, there are several types of processes by which detergentgranules or powders can be prepared. One type of process involvesspray-drying an aqueous detergent slurry in a spray-drying tower toproduce highly porous spray dried particulate material. In another typeof process, various detergent components are dry mixed after which theyare combined together with a binder such as a nonionic or anionicsurfactant. In both processes, the most important factors which governthe density of the resulting detergent granules are the density,porosity and surface area of the various starting materials and theirrespective chemical composition. These parameters, however, can only bevaried within a limited range. Thus, a substantial bulk density increasecan only be achieved by additional processing steps which lead todensification of the detergent granules.

There have been many attempts in the art for providing processes whichincrease the density of detergent material. Particular attention hasbeen given to densification of spray-dried particulate material by posttower treatment. For example, one attempt involves a batch process inwhich spray-dried or granulated detergent powders containing sodiumtripolyphosphate and sodium sulfate are densified and spheronized in aMarumerizer®. This apparatus comprises a substantially horizontal,roughened, rotatable table positioned within and at the base of asubstantially vertical, smooth walled cylinder. This process, however,is essentially a batch process and is therefore less suitable for thelarge scale production of detergent powders. Other attempts have beenmade to provide a continuous processes for increasing the density of“post-tower” or spray dried particulate material.

All of the aforementioned processes are directed primarily to densifyingor otherwise processing spray dried particulate material. Currently, therelative amounts and types of materials subjected to spray dryingprocesses in the production of detergent granules has been limited. Forexample, it has been difficult to attain high levels of surfactant inthe resulting detergent composition, a feature which facilitatesproduction of low dosage detergents. Thus, it would be desirable to havea process by which detergent compositions can be produced without havingthe limitations imposed by conventional spray drying techniques. To thatend, the art is also replete with disclosures of processes which entailagglomerating detergent compositions. For example, attempts have beenmade to agglomerate detergent builders by mixing zeolite and/or layeredsilicates in a mixer to form free flowing agglomerates.

However, in all of the aforementioned processes, continuous large-scaleproduction has its difficulties, especially relative to obtainingacceptable product consistently and with minimal wear and tear on themanufacturing equipment. For instance, while certain mixer/densifierswork extremely well at the lab scale, their performance is not alwaysreproducible in large-scale commercial continuous manufacturingfacilities. One problem experienced with large-scale detergentmanufacturing using the aforementioned processes involves detergentproduct that has a wide particle size range. This, in effect, produces adetergent product having some “undersized” or very “fine” particles andsome very large or “oversized” particles which is not only unacceptableto the consumer, but leads to product performance inconsistencies.Specifically, a particular dose or scoop of detergent product used bythe consumer may not have the targeted ingredient levels because adisproportionate amount of “fines” or “overs” is in the dose as a resultof the settling of the fines to the bottom of the product box duringstorage and handling. This inevitably leads to undesirable cleaningperformance, and at a minimum, inconsistencies including performance.One solution to this problem is simply to recycle the “fines” and grindthe “overs” to the desired size, but this increases the manufacturingcosts significantly.

Another problem that has arisen involves excessive vibration of therotating shafts in commercial scale mixer/densifiers, especially inlarge moderate speed mixer/densifiers, which can have deleteriouseffects on the detergent composition produced as well as on themixer/densifiers and other closely located manufacturing equipment. Thisproblem can also lead to structural damage to the manufacturing buildingfor which substantial expenditures may be required for repairs. The useof additional mechanical apparatus such as tuned dampers positioned onthe shaft only add to the cost of manufacturing and can interfere itswith operation in that the tuned damper apparatus inside the mixerprovides a place for detergent to accumulate, thereby deleteriouslyaffecting mixer operation. Thus, there remains a need for a means bywhich commercial scale moderate speed mixer/densifiers used to producelow dosage, high density detergent compositions can be operatedcontinuously without significant mechanical vibration and damageresulting therefrom.

Accordingly, there remains a need in the art to have a process forcontinuously producing a high density detergent composition which hasimproved physical properties including a more narrow particle sizedistribution. There is also a need for such a process that involves amoderate speed mixer/densifier that experiences minimal mechanicalvibration, and yet, produces a superior detergent composition. Also,there remains a need for such a process which is more efficient andeconomical to facilitate large-scale production of low dosage or compactdetergents.

BACKGROUND ART

The following references are directed to densifying spray-diedparticulate material: Appel et al, U.S. Pat. No. 5,133,924 (Lever);Bortolotti et al, U.S. Pat. No. 5,160,657 (Lever); Johnson et al,British patent No. 1,517,713 (Unilever); and Curtis, European PatentApplication 451,894. The following references are directed to producingdetergents by agglomeration: Capeci et al, U.S. Pat. No. 5,366,652;Capeci et al, U.S. Pat. No. 5,486,303; Capeci et al, U.S. Pat. No.5,489,392; Capeci et al, U.S. Pat. No. 5,516,448; Beerse et al, U.S.Pat. No. 5,108,646 (Procter & Gamble). Other relevant prior artincludes: PCT Publication WO 98/14558; PCT Publication WO 98/14557; PCTPublication WO 98/14556; PCT Publication WO 98/14553; PCT Publication WO98/14552; PCT Publication WO 98/14555; PCT Publication WO 98/1454; PCTPublication WO 98/1455 1; and PCT Publication WO 98/11193 and WO98/24876.

SUMMARY OF THE INVENTION

The present invention meets the aforementioned needs in the art byproviding a process which continuously produces a high density detergentcomposition via a process during which high density detergentagglomerates are produced by feeding a surfactant paste and dry startingdetergent material into a cylindrically-shaped/moderate speedmixer/densifier having a centrally positioned rotating shaft and atleast one high speed chopper. In the process, surfactant paste and otherdry starting detergent materials are inputted directly into the moderatespeed mixer/densifier to form detergent agglomerates which are thencooled and/or dried. Importantly, the surfactant paste is inputted alongthe length of the moderate speed mixer/densifier to ensure optimalbuild-up agglomeration. The resulting agglomerates from the process arefree flowing, more uniform in size and shape, and higher in surfactantlevel and are ready for incorporation into a commercially viable lowdosage or “compact” detergent product.

As used herein, the term “agglomerates” refers to particles formed bybuild-up agglomeration of starting detergent ingredients typicallyhaving a smaller mean particle size than the formed agglomerates. Allpercentages and ratios used herein are expressed as percentages byweight (anhydrous basis) unless otherwise indicated. All documents areincorporated herein by reference. All viscosities referenced herein aremeasured at 70° C. (±5° C.) and at shear rates of about 10 to 100 sec⁻¹.

In accordance with one aspect of the invention, a process for preparinga crisp, free flowing, high density detergent composition is provided.The process comprises the steps of: (a) continuously adding a detergentsurfactant paste and dry starting detergent material into a moderatespeed mixer/densifier to form detergent agglomerates, wherein themoderate speed mixer/densifier includes a centrally rotating shaft andat least one high speed chopper located on the inside wall along thelongitudinal length of said moderate speed mixer/densifier, wherein saidsurfactant paste is inputted along said longitudinal length of saidmoderate speed mixer/densifier; and (b) drying or cooling the detergentagglomerates so as to form the detergent composition. In another aspectof the invention, an acid precursor to a detergent surfactant is used inplace of the surfactant paste to provide the detergent composition inagglomerate form.

In yet another aspect of the invention, another process for continuouslypreparing a detergent composition is provided. This process comprisesthe steps of: (a) continuously adding dry starting detergent materialinto a mixer to mixed dry detergent material; (b) inputting mixed drydetergent material and a detergent surfactant paste into a moderatespeed mixer/densifier to form detergent agglomerates, wherein moderatespeed mixer/densifier includes a centrally rotating shaft and at leastone high speed chopper located on the inside wall along the longitudinallength of moderate speed mixer/densifier, wherein surfactant paste isinputted along longitudinal length of moderate speed mixer/densifier soas to mix with mixed dry detergent material after mixed dry detergentmaterial enters moderate speed mixer/densifier; and (c) drying orcooling the detergent agglomerates so as to form the detergentcomposition.

Accordingly, it is an advantage of the invention to provide a processfor continuously producing a high density detergent composition using amoderate speed mixer/densifier which experiences less vibration andproduces a composition having a more narrow particle size distribution.Also, it is an advantage of the invention to provide such a processwhich is more efficient and economical to facilitate large-scaleproduction of low dosage or compact detergents. These and other objects,features and attendant advantages of the present invention will becomeapparent to those skilled in the art from a reading of the followingdetailed description of the preferred embodiments and the appendedclaims.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Process

The present process can be used in the production of low dosage, highdensity detergent compositions containing agglomerates produced directlyfrom dry starting detergent ingredients and a surfactant paste orprecursor thereof. It has been surprisingly found that by using a singlemoderate speed mixer/densifier, a superior detergent composition in theform of agglomerates can be produced. The resulting detergentagglomerates have a tighter or more narrow particle size distributionwhich leads to the need for less recycling of undersized agglomeratesback through the mixer/densifier and/or the need to grind oversizeddetergent agglomerates. Additionally, by inputting the surfactant pasteor precursor thereof directly into the moderate speed mixer/densifieralong its longitudinal length, sufficient mixing for rapid build-upagglomeration occurs. The resulting detergent agglomerates are also morespherical in appearance which is aesthetically desirable for modern daycompact detergent products. Further, the process only requires onemoderate speed mixer/densifier to produce the final detergentcomposition which is more economical than previous multi-step mixerprocesses.

In the first step of the process, the invention entails continuouslymixing into a moderate speed mixer/densifier at least two streams ofstarting detergent ingredients including a surfactant paste stream and adry starting detergent material stream. The surfactant paste added tothe moderate speed mixer/densifier is in aqueous paste form and is addedin amounts of from about 25% to about 65%, preferably from about 35% toabout 55% and, most preferably from about 38% to about 44%, by weight ofthe total input stream to the mixer/densifier. Preferably, the drystarting detergent material comprises from about 20% to about 50%,preferably from about 25% to about 45%, and most preferably from about30% to about 40%, of an aluminosilicate or zeolite builder, and fromabout 10% to about 40%, preferably from about 15% to about 30%, and mostpreferably from about 15% to about 25%, by weight of a sodium carbonate.The dry starting detergent material preferably is not a spray-driedparticulate material, and does not contain a detergent surfactant.

While not intending to be bound by theory, it is believed that byinputting surfactant paste along the longitudinal length of acylindrically-shaped moderate speed mixer/densifier having a centrallyrotating shaft to which one or more of a variety of agglomeration toolsare attached and at least one high speed chopper located on the insidewall of the mixer/densifier, optimal build-up agglomeration results. Inpreferred modes of the process, several high speed choppers are used inthe moderate speed mixer/densifier, for example, at least two,preferably at least four, and most preferably at least six high speedchoppers are used. Certain moderate speed mixer/densifiers can beequipped with as many as twelve high speed choppers to improve build-upagglomeration. Also, various multi-blade configurations can be used onthe high speed choppers to optimize their effectiveness. The tip speedof any one of these choppers is preferably from about 1 m/s to about 60m/s, more preferably from about 10 m/s to about 45 m/s, and mostpreferably from about 20 m/s to about 30 m/s. As those skilled in theart will appreciate, the tip speed can be adjusted with a variable speeddrive apparatus connected to the high speed choppers. The rotationalspeed of any one of these choppers is preferably from about 200 rpm toabout 5000 rpm, more preferably from about 1500 rpm to about 4500 rpm,and most preferably from about 3000 rpm to about 4000 rpm.

By inputting the surfactant paste near, preferably within 25 cm or lessfrom the high speed choppers, it has been found that even more optimalbuild-up agglomeration occurs. Most optimal results are achieved byensuring that at least 80% of the surfactant paste is added into theface of, underneath, or from within the high speed choppers. Theresulting detergent agglomerates have the previously mentionedcharacteristics of a more narrow particle size distribution, morespherical-shaped agglomerates, and even have the ability to containhigher levels of surfactant. The higher level of surfactant in thedetergent agglomerates is extremely beneficial as it allows foradditional detergent ingredients to be added to the composition withoutsacrificing density or the degree of compactness of the detergentproduct.

Previous agglomeration processes which employ a high speed mixer formixing the surfactant or precursor thereof and dry detergent materialprior to the moderate speed mixer/densifier typically do not provide thedesired narrow particle size distribution. In fact, such processesproduce a substantial amount of undersized or fine particles which arerecycled back through the process. It is not uncommon for 50% by weightof the agglomerates produced in such prior processes to requirerecycling and/or grinding to provide the desired mean particle size. Inthat regard, the present process dramatically reduces the amount ofundersized and oversized detergent agglomerates produced which rendersthe process more efficient, economical and flexible. The particle sizedistribution is also more narrow. Specifically, the mean particle sizeof the agglomerates is preferably from about 150 microns to about 2000microns, more preferably from about 250 microns to about 1000 microns,and most preferably from about 300 microns to about 500 microns.

Preferably, the surfactant paste and the dry starting detergent materialare continuously added to the moderate speed mixer/densifier in weightratio ranges described herein so as to ensure production of the desiredfree flowing, crisp, high density detergent composition. Preferably, theweight ratio of the surfactant paste to the dry starting detergentmaterial is from about 1:10 to about 10:1, more preferably from about1:4 to about 4:1 and, most preferably from about 2:1 to about 2:3.

The moderate speed mixer/densifier used in the present process includesliquid distribution and agglomeration tools so that both techniques canbe carried forth simultaneously. As described, the liquid or pastedistribution is accomplished with the use of at least one high speedchopper positioned on the inside wall along the length of the moderatespeed mixer/densifier. For purposes of ensuring effective liquid orsurfactant paste distribution and adequate build-up agglomeration, thehigh speed chopper preferably has a tip speed as mentioned above. Tofurther facilitate build-up agglomeration, the moderate speedmixer/densifier is equipped with ploughs and/or other tools to ensureeffective build-up agglomeration in the process. It is preferable tohave the moderate speed mixer/densifier to be, for example, a Lödige KM(Ploughshare) mixer, Drais® K-T 160 mixer or similar brand mixer. Themean residence time in the moderate speed mixer/densifier is typicallyfrom about 0.1 minutes to about 20 minutes, most typically the residencetime is about 0.5 minutes to about 10 minutes, wherein the meanresidence time is conveniently and accurately measured by measuring thesteady-state weight of the mixer/densifier (Kg) and dividing by thethroughput (Kg/hr) of the mixer.

The process also exhibits reduced mechanical vibration in the moderatespeed mixer/densifier. While not intending to be bound by theory, it isbelieved that the detergent surfactant paste input along the length ofthe moderate speed mixer/densifier, through for example, an input tubeor nozzle, leads to a reduction of detergent material build-up on theinside wall of the moderate speed mixer/densifier. The detergentmaterial “wall” that typically forms in prior art processes frequentlycauses a weight imbalance during mixer operation leading to undesirablemechanical vibration, especially of the centrally rotating shaft in themoderate speed mixer/densifier. By using the instant process, thepreferred peak vibration range for the shaft is from about −1.0 G toabout 1.0 G, more preferably from about −0.5 G to about 0.5 G, and mostpreferably from about −0.25 G to about 0.25 G, in a frequency range offrom about 10 Hz to about 20 Hz as measured at the mid-span length ofthe shaft. Such peak vibration ranges represent a dramatic improvementover peak vibrations typically experienced in commercial scalemanufacturing facilities which can be on the order of ±3.5 G. The peakvibration is preferably measured using 90 second intervals. As thoseskilled in the art will appreciate, such peak vibration measurements areeasily completed using a conventional accelerometer (available from PCB308B ICP Company, Buffalo, N.Y.).

For example, during continuous operation of the process, the vibrationof shaft is recorded using the accelerometer attached to a power supply(e.g., PCB 480E090 from ICP Company, and a battery operated digital taperecorder such as the Sony TCD-D3 DAT recorder). The recorder and powersupply are mounted in a waterproof, shock proof enclosure (such as theCarlon CJ1085 Enclosure). The sensor is attached to the shaft by meansof dental cement or other rigid adhesive and is positioned such thatradial shaft vibration is measured. The vibration is recorded for atleast 2 hours, preferably for 4 hours. Upon completion of the run, thetape recorder is removed from the enclosure and played back. The data isplotted in 90 second intervals on either a digital or analog plottingdevice (such as the Hewlett-Packard 3560A or 35670A analyzers). The peakand rms values of the vibration can be determined from a PC-basedsoftware program such as Excel or Matlab.

While not intending to be bound by theory, the negative peak vibrationsassociated with the moderate speed mixer/densifier are especiallyexacerbated when the so-called “detergent wall” is present on the innersurface of the moderate speed mixer/densifier. During the process, anoptional detergent coating or wall of at least about a 1 mm can cover aportion of the inner wall surface of the moderate speed mixer/densifier.The portion of the inner wall covered by this coating having a minimumthickness of 1 mm can be substantial (up to 100% of the inner surfacecovered) or a mere 50% can be covered. The presence of this detergentcoating provides an irregular surface contour against which the ploughsare contacted during rotation of the shaft of the moderate speedmixer/densifier. This irregular surface results in the shaft beingsubjected to irregular forces, thereby further enhancing the overallmechanical vibration. This process wherein the detergent surfactantpaste is added directly to, and along the length of the moderate speedmixer/densifier, however, eliminates or minimizes this additionalmechanical vibration.

The preferred density of the resulting detergent agglomerates exitingthe moderate speed mixer/densifier is at least about 650 g/l, morepreferably from about 700 g/l to about 900 g/l. The particle porosity ofthe resulting detergent agglomerates of the composition is preferably ina range from about 5% to about 20%, more preferably at about 10%. Thedetergent agglomerates can be dried in a fluid bed dryer or cooled in afluid bed cooler or similar apparatus which are well known in the art.While the detergent agglomerates exiting the moderate speedmixer/densifier and fluid bed cooler or dryer are ready for packagingand sale as a low dosage, compact detergent product at this point, theycan be subjected to one or more optional processing steps.

Optional Process Steps

Optionally, a mixer may be used to pre-mix the starting dry detergentmaterials. Any suitable mixer can be used for such purposes includingbut not limited to a Shugi Granulator or a Lödige CB 30 mixer. Anotheroptional process step involves adding a coating agent to improveflowability and/or minimize over agglomeration of the detergentcomposition in one or more of the following locations of the instantprocess: (1) the coating agent can be added directly into the fluid bedcooler or fluid bed dryer if used; (2) the coating agent may be addedbetween the fluid bed dryer and the fluid bed cooler if both are used;(3) the coating agent may be added between the fluid bed dryer or coolerand the moderate speed mixer/densifier; and/or (4) the coating agent maybe added directly to the moderate speed mixer/densifier. It should beunderstood that the coating agent can be added in any one or acombination of locations mentioned herein. The coating agent ispreferably added into the moderate speed mixer/densifier as well as intothe fluid bed dryer.

The coating agent is preferably selected from the group consisting ofaluminosilicates, silicates, carbonates and mixtures thereof. Thecoating agent not only enhances the free flowability of the resultingdetergent composition which is desirable by consumers in that it permitseasy scooping of detergent during use, but also serves to controlagglomeration by preventing or minimizing over agglomeration, especiallywhen added directly to the moderate speed mixer/densifier. As thoseskilled in the art are well aware, over agglomeration can lead to veryundesirable flow properties and aesthetics of the final detergentproduct.

Optionally, the process can comprises the step of spraying an additionalbinder in the moderate speed mixer/densifier and/or in the fluid beddryer or cooler. A binder is added for purposes of enhancingagglomeration by providing a “binding” or “sticking” agent for thedetergent components. The binder is preferably selected from the groupconsisting of water, anionic surfactants, nonionic surfactants,polyethylene glycol, polyvinyl pyrrolidone polyacrylates, citric acidand mixtures thereof. Other suitable binder materials including thoselisted herein are described in Beerse et al, U.S. Pat. No. 5,108,646(Procter & Gamble Co.), the disclosure of which is incorporated hereinby reference.

Other optional steps contemplated by the present process includescreening the oversized and undersized detergent agglomerates in ascreening apparatus which can take a variety of forms including but notlimited to conventional screens chosen for the desired particle size ofthe finished detergent product. Another optional step of the instantprocess entails finishing the resulting detergent agglomerates by avariety of processes including spraying and/or admixing otherconventional detergent ingredients. For example, the finishing stepencompasses spraying perfumes, brighteners and enzymes onto the finishedagglomerates to provide a more complete detergent composition. Suchtechniques and ingredients are well known in the art.

Detergent Surfactant Paste

The detergent surfactant paste used in the process is preferably in theform of an aqueous viscous paste, other forms are also contemplated bythe invention, such as the acid precursor of a surfactant paste. If anacid precursor is used, the dry detergent material will include aneutralizing agent such as sodium carbonate. The viscous surfactantpaste used herein has a viscosity of from about 5,000 cps to about100,000 cps, more preferably from about 10,000 cps to about 80,000 cps,and contains at least about 10% water, more preferably at least about20% water. The viscosity is measured at 70° C. and at shear rates ofabout 10 to 100 sec⁻¹. Furthermore, the surfactant paste, if used,preferably comprises a detersive surfactant in the amounts specifiedpreviously and the balance water and other conventional detergentingredients.

The surfactant itself, in the viscous surfactant paste, is preferablyselected from anionic, nonionic, zwitterionic, ampholytic and cationicclasses and compatible mixtures thereof. Detergent surfactants usefulherein are described in U.S. Pat. No. 3,664,961, Norris, issued May 23,1972, and in U.S. Pat. No. 3,919,678, Laughlin et al., issued Dec. 30,1975, both of which are incorporated herein by reference. Usefulcationic surfactants also include those described in U.S. Pat. No.4,222,905, Cockrell, issued Sep. 16, 1980, and in U.S. Pat. No.4,239,659, Murphy, issued Dec. 16, 1980, both of which are alsoincorporated herein by reference. Of the surfactants, anionics andnonionics are preferred and anionics are most preferred.

Nonlimiting examples of the preferred anionic surfactants useful in thesurfactant paste include the conventional C₁₁-C₁₈ alkyl benzenesulfonates (“LAS”), primary, branched-chain and random C₁₀-C₂₀ alkylsulfates (“AS”), the C₁₀-C₁₈ secondary (2,3) alkyl sulfates of theformula CH₃(CH₂)_(x)(CHOSO₃ ⁻M⁺)CH₃ and CH₃(CH₂)_(y)(CHOSO₃ ⁻M⁺)CH₂CH₃where x and (y+1) are integers of at least about 7, preferably at leastabout 9, and M is a water-solubilizing cation, especially sodium,unsaturated sulfates such as oleyl sulfate, and the C₁₀-C₁₈ alkyl alkoxysulfites (“AE_(x)S”; especially EO 1-7 ethoxy sulfates).

Optionally, other exemplary surfactants useful in the paste of theinvention include and C₁₀-C₁₈ alkyl alkoxy carboxylates (especially theEO 1-5 ethoxycarboxylates), the C₁₀₋₁₈ glycerol ethers, the C₁₀-C₁₈alkyl polyglycosides and their corresponding sulfated polyglycosides,and C₁₂-C₁₈ alpha-sulfonated fatty acid esters. If desired, theconventional nonionic and amphoteric surfactants such as the C₁₂-C₁₈alkyl ethoxylates (“AE”) including the so-called narrow peaked alkylethoxylates and C₆-C₁₂ alkyl phenol alkoxylates (especially ethoxylatesand mixed ethoxy/propoxy), C₁₂-C₁₈ betaines and sulfobetaines(“sultaines”), C₁₀-C₁₈ amine oxides, and the like, can also be includedin the overall compositions. The C₁₀-C₁₈ N-alkyl polyhydroxy fatty acidamides can also be used. Typical examples include the C₁₂-C₁₈N-methylglucamides. See WO 9,206,154. Other sugar-derived surfactantsinclude the N-alkoxy polyhydroxy fatty acid anodes, such as C₁₀-C₁₈N-(3-methoxypropyl) glucamide. The N-propyl through N-hexyl C₁₂-C₁₈glucamides can be used for low sudsing. C₁₀-C₂₀ conventional soaps mayalso be used. If high sudsing is desired, the branched-chain C₁₀-C₁₆soaps may be used. Mixtures of anionic and nonionic surfactants areespecially useful. Other conventional useful surfactants are listed instandard texts.

Dry Detergent Material

The starting dry detergent material of the present process preferablycomprises a detergent aluminosilicate builder which are referenced asaluminosilicate ion exchange materials and sodium carbonate. Thealuminosilicate ion exchange materials used herein as a detergentbuilder preferably have both a high calcium ion exchange capacity and ahigh exchange rate. Without intending to be limited by theory, it isbelieved that such high calcium ion exchange rate and capacity are afunction of several interrelated factors which derive from the method bywhich the aluminosilicate ion exchange material is produced. In thatregard, the aluminosilicate ion exchange materials used herein arepreferably produced in accordance with Corkill et al, U.S. Pat. No.4,605,509 (Procter & Gamble), the disclosure of which is incorporatedherein by reference.

Preferably, the aluminosilicate ion exchange material is in “sodium”form since the potassium and hydrogen forms of the instantaluminosilicate do not exhibit as high of an exchange rate and capacityas provided by the sodium form. Additionally, the aluminosilicate ionexchange material preferably is in over dried form so as to facilitateproduction of crisp detergent agglomerates as described herein. Thealuminosilicate ion exchange materials used herein preferably haveparticle size diameters which optimize their effectiveness as detergentbuilders. The term “particle size diameter” as used herein representsthe average particle size diameter of a given aluminosilicate ionexchange material as determined by conventional analytical techniques,such as microscopic determination and scanning electron microscope(SEM). The preferred particle size diameter of the aluminosilicate isfrom about 0.1 micron to about 10 microns, more preferably from about0.5 microns to about 9 microns. Most preferably, the particle sizediameter is from about 1 microns to about 8 microns.

Preferably, the aluminosilicate ion exchange material has the formula

Na_(z)[(AlO₂)_(z).(SiO₂)_(y) ]xH₂O

wherein z and y are integers of at least 6, the molar ratio of z to y isfrom about 1 to about 5 and x is from about 10 to about 264. Morepreferably, the aluminosilicate has the formula

Na₁₂[(AlO₂)₁₂.(SiO₂)₁₂ ]xH₂O

wherein x is from about 20 to about 30, preferably about 27. Thesepreferred aluminosilicates are available commercially, for example underdesignations Zeolite A, Zeolite B and Zeolite X. Alternatively,naturally-occurring or synthetically derived aluminosilicate ionexchange materials suitable for use herein can be made as described inKrummel et al, U.S. Pat. No. 3,985,669, the disclosure of which isincorporated herein by reference.

The aluminosilicates used herein are further characterized by their ionexchange capacity which is at least about 200 mg equivalent of CaCO₃hardness/gram, calculated on an anhydrous basis, and which is preferablyin a range from about 300 to 352 mg equivalent of CaCO₃ hardness/gram.Additionally, the instant aluminosilicate ion exchange materials arestill further characterized by their calcium ion exchange rate which isat least about 2 grains Ca⁺⁺/gallon/minute/-gram/gallon, and morepreferably in a range from about 2 grainsCa⁺⁺/gallon/minute/-gram/gallon to about 6 grainsCa⁺⁺/gallon/minute/-gram/gallon.

Adjunct Detergent Ingredients

The starting dry detergent material in the present process can includeadditional detergent ingredients and/or, any number of additionalingredients can be incorporated in the detergent composition duringsubsequent steps of the present process. These adjunct ingredientsinclude other detergency builders, bleaches, bleach activators, sudsboosters or suds suppressers, anti-tarnish and anticorrosion agents,soil suspending agents, soil release agents, germicides, pH adjustingagents, non-builder alkalinity sources, chelating agents, smectiteclays, enzymes, enzyme-stabilizing agents and perfume. See U.S. Pat. No.3,936,537, issued Feb. 3, 1976 to Baskerville, Jr. et al., incorporatedherein by reference.

In order to make the present invention more readily understood,reference is made to the following examples, which are intended to beillustrative only and not intended to be limiting in scope.

EXAMPLE

This Example illustrates the process of the invention which producesfree flowing, crisp, high density detergent composition. Two feedstreams of various detergent starting ingredients are continuously fed,at a rate of 1320 kg/hr, into a Lödige KM 600 moderate speedmixer/densifier, one of which comprises an aqueous surfactant paste andthe other stream containing starting dry detergent material containingaluminosilicate and sodium carbonate. The Lödige KM 600 moderate speedmixer/densifier has four high speed choppers, each having a tip speed of15 m/s and a rotational speed of 3800 rpm, positioned on the inside wallalong the longitudinal length of the Lödige KM 600. The surfactant pasteis a non-linear viscolelastic surfactant paste having a viscosity of100,000 cps (at 70° C. and at a shear rate of 1 sec⁻¹) and is inputtedat four locations within 25 cm of each high speed chopper. The drydetergent materials are added via an inlet at the top-front of theLödige KM 600 moderate speed mixer/densifier. The resulting detergentagglomerates are then fed to a fluid bed dryer and then to a fluid bedcooler, the mean residence time being about 10 minutes and 15 minutes,respectively. A coating agent, aluminosilicate, is fed after themoderate speed mixer/densifier to control and prevent overagglomeration. The composition of the detergent agglomerates exiting thefluid bed cooler is set forth in Table I below:

TABLE I Component % Weight of Total Feed C₁₄₋₁₅ alkyl sulfate 22.5C_(12.3) linear alkylbenzene sulfonate 2.5 Aluminosilicate 35.2 Sodiumcarbonate 21.0 Polyethylene glycol (MW 4000) 1.5 Misc. (water, etc.)12.3 100.0

Additional detergent ingredients including perfumes, enzymes, and otherminors are sprayed onto the agglomerates described above in thefinishing step to result in a finished detergent composition which isadmixed with spray dried particulate material in a 60:40 weight ratio(agglomerates: spray dried particulate material). The relativeproportions of the overall finished detergent composition produced bythe process of instant process is presented in Table II below:

TABLE II Component (% weight) C₁₄₋₁₅ alkyl sulfate/C_(12.3) linearalkylbenzene sulfonate 16.3 Neodol 23-9.5¹ 1.8 Polyacrylate (MW = 4500)3.2 Polyethylene glycol (MW = 4000) 1.7 Sodium Sulfate 5.7Aluminosilicate 26.3 Sodium carbonate 33.1 Protease enzyme 0.4 Amylaseenzyme 0.1 Lipase enzyme 0.2 Cellulase enzyme 0.1 Minors (water,perfume, etc.) 11.1 100.0

The density of the resulting fully formulated detergent composition is621 g/l, the mean particle size is 400 microns. The density of theagglomerates alone is 810 g/l and the mean particle size is 450 microns.

Having thus described the invention in detail, it will be clear to thoseskilled in the art that various changes may be made without departingfrom the scope of the invention and the invention is not to beconsidered limited to what is described in the specification.

What is claimed is:
 1. A process for continuously preparing a detergentcomposition comprising the steps of: (a) continuously adding a detergentsurfactant paste and dry starting detergent material into a moderatespeed mixer/densifier to form detergent agglomerates, wherein saidmoderate speed mixer/densifier includes a centrally rotating shaft andat least four high speed choppers located along the longitudinal lengthof said moderate speed mixer/densifier, wherein said surfactant paste isinputted at at least four locations on the inside wall along saidlongitudinal length of said moderate speed mixer/densifier, each of saidlocations being within about 25 cm of a chopper, so as to mix said pastewith said dry detergent material after said dry detergent materialenters said moderate speed mixer/densifier, and wherein saidmixer/densifier is operated without tuned dampers; and (b) drying orcooling the detergent agglomerates so as to form the detergentcomposition.
 2. A process of claim 1 wherein the density of saiddetergent composition is at least 650 g/l.
 3. A process of claim 1wherein the mean particle size of said detergent agglomerates is from150 microns to 2000 microns.
 4. The process of claim 1 wherein the meanparticle size of said detergent agglomerates is from about 250 micronsto about 100 microns.
 5. A process of claim 1 wherein the peak vibrationof said shaft is from −1.0 G to 1.0 G in a frequency range of from 10 Hzto 20 Hz at the mid-span length of said shaft.
 6. The process of claim 1further comprising the step of adding a coating agent selected from thegroup consisting of aluminosilicates, carbonates, silicates and mixturesthereof into said moderate speed mixer/densifier.
 7. The process ofclaim 1 wherein the mean residence time of said detergent agglomeratesin said moderate speed mixer/densifier is in range from about 0.1minutes to about 20 minutes.
 8. The process of claim 1 wherein said fourhigh speed choppers have a tip speed of from about 1 m/s to about 60m/s.
 9. The process of claim 1 wherein said dry detergent material isselected from the group consisting of carbonates, aluminosilicates andmixtures thereof.
 10. The process of claim 1 wherein said surfactantpaste has a viscosity of from about 1000 cps to about 100,000 cps.
 11. Aprocess for continuously preparing a detergent composition comprisingthe steps of: continuously adding an acid precursor of a detergentsurfactant and dry starting detergent material into a moderate speedmixer/densifier to form detergent agglomerates, wherein said moderatespeed mixer/densifier includes a centrally rotating shaft and at leastfour high speed choppers located on the inside wall along thelongitudinal length of said moderate speed mixer/densifier, wherein saidsurfactant precursor is inputted at at least four locations along saidlongitudinal length of said moderate speed mixer/densifier, each of saidlocations being within about 25 cm of a chopper, so as to mix saidprecursor with said dry detergent material after said dry detergentmaterial enters said moderate speed mixer/densifier, and wherein saidmixer/densifier is operated without tuned dampers; and (b) drying orcooling the detergent agglomerates so as to form the detergentcomposition.
 12. A process for continuously preparing a detergentcomposition comprising the steps of: continuously adding dry startingdetergent material into a mixer to form mixed dry detergent material;inputting said mixed dry detergent material and a detergent surfactantpaste into a moderate speed mixer/densifier to form detergentagglomerates, wherein said moderate speed mixer/densifier includes acentrally rotating shaft and at least four high speed choppers locatedon the inside wall along the longitudinal length of said moderate speedmixer/densifier, wherein said surfactant paste is inputted at at leastfour locations along said longitudinal length of said moderate speedmixer/densifier, each of said locations being within about 25 cm of achopper, so as to mix said paste with said mixed dry detergent materialafter said mixed dry detergent material enters said moderate speedmixer/densifier, wherein said mixer/densifier is operated without tuneddampers; and (c) drying or cooling the detergent agglomerates so as toform the detergent composition.
 13. The process of claim 12 wherein saidfour high speed choppers have a tip speed of from about 1 m/s to about60 m/s.